If you paid via PayPal:
1. Go to PayPal and log into your account on the system.
2. Once inside, you should see payment history, including payments to Podomatic. View details on one payment to Podomatic.
3. At the top of the detail page, you will see a link indicating "In Reference To" something that looks like the letter S- followed by a bunch of numbers and letters. Click that link.
4. The next page you see should have a button on the lower right that says "Cancel Subscription." Click the button to cancel.